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  • Organic Chemistry  (5)
  • Fluorochrome-labeled capillaries  (2)
  • Liesegang rings  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Pulmonary uptake of bupivacaine in isolated perfused rat lung (1995)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 351 (1995), S. 99-106 
    Details
    ISSN: 1432-1912
    Keywords: Lung perfusion ; Bupivacaine ; Fluorochrome-labeled capillaries ; First-pass retention ; Inulin ; Tritium-labeled water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ability of rat lung to remove the local anaesthetic drug bupivacaine from the blood was studied in isolated organs which were perfused either in an open (single-pass mode) or in a closed system (recirculating medium). Isolated perfused rat lungs exhibited a very low capacity to metabolize bupivacaine within 3 h during which the drug circulated continuously through the organ. The clearance values differed only by 0.2 ml/min from the control parameters in sham perfusions. The calculated extraction ratio was 0.2% and the elimination half-life was about 210 min. The volume of distribution of bupivacaine was 133 ml which remarkably surmounted the reference values obtained for sham perfusions. The distribution of bupivacaine into the pulmonary tissue was investigated applying the multiple indicator dilution technique to isolated lungs perfused in the single-pass mode. The mean elimination time of model compounds for distribution into the intravascular space, 14C-inulin, and the total water space, 3H-water, were 68 and 75 s at a flow rate of 6 ml/min. The volume of distribution was 5.9 ml for inulin and 6.5 ml for water. The mean transit time for concomitantly injected bupivacaine was 221 s and the volume of distribution was 14.4 ml. The respective parameters of sham perfusions performed without an isolated organ were substantially lower, i.e. mean elimination time 50, 50 and 61 s and distribution volume 4.9, 5.0 and 6.1 ml for inulin, water and bupivacaine. The volume of distribution during single-pass contact of bupivacaine to lung was not substantially influenced by an increase of the flow rate from 6 to 9 and 12 ml/min whereas the mean transit time dropped from 221 to 121 and 108 s, respectively. These results support the assumption that bupivacaine is extensively retained by the pulmonary tissue and that elimination of bupivacaine by metabolism can be neglegted for lung. The hemodynamic parameters of bronchiolar perfusion in the artificially perfused lung were determined using two fluorochrome-labeled macromolecular proteins, i.e. fluorescein-isothiocyanate (FITC)- and lissamine-rhodamine-B 200 (RB 200)-labeled globulin. After 10 min of perfusion at a flow rate of 12 ml/min in the closed system an area of 10.8070 of the peribronchiolar tissue area contained the dye-label FITC. A very similar index (10.1%) of dye-coloured capillaries was obtained when the lungs of anaesthetized rats were examined 10 min after intravenous injection of the fluorochrome into the pulmonary artery in vivo. In isolated perfused rat lungs receiving both FITC and RB 200 59.5% of FITC-labeled capillaries were reached by the second fluorochrome within 2 s. This fraction accounted for 93.3% after 10 s of circulation time. This proves that isolated rat lungs were well perfused in vitro.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169070
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  • 2
    Electronic Resource
    Electronic Resource
    Pulmonary uptake of bupivacaine in isolated perfused rat lung (1994)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 351 (1994), S. 99-106 
    Details
    ISSN: 1432-1912
    Keywords: Key words Lung perfusion ; Bupivacaine ; Fluorochrome-labeled capillaries ; First-pass retention ; Inulin ; Tritium-labeled water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ability of rat lung to remove the local anaesthetic drug bupivacaine from the blood was studied in isolated organs which were perfused either in an open (single-pass mode) or in a closed system (recirculating medium). Isolated perfused rat lungs exhibited a very low capacity to metabolize bupivacaine within 3 h during which the drug circulated continuously through the organ. The clearance values differed only by 0.2 ml/min from the control parameters in sham perfusions. The calculated extraction ratio was 0.2% and the elimination half-life was about 210 min. The volume of distribution of bupivacaine was 133 ml which remarkably surmounted the reference values obtained for sham perfusions. The distribution of bupivacaine into the pulmonary tissue was investigated applying the multiple indicator dilution technique to isolated lungs perfused in the single-pass mode. The mean elimination time of model compounds for distribution into the intravascular space, 14C-inulin, and the total water space, 3H-water, were 68 and 75 s at a flow rate of 6 ml/min. The volume of distribution was 5.9 ml for inulin and 6.5 ml for water. The mean transit time for concomitantly injected bupivacaine was 221 s and the volume of distribution was 14.4 ml. The respective parameters of sham perfusions performed without an isolated organ were substantially lower, i.e. mean elimination time 50, 50 and 61 s and distribution volume 4.9, 5.0 and 6.1 ml for inulin, water and bupivacaine. The volume of distribution during single-pass contact of bupivacaine to lung was not substantially influenced by an increase of the flow rate from 6 to 9 and 12 ml/min whereas the mean transit time dropped from 221 to 121 and 108 s, respectively. These results support the assumption that bupivacaine is extensively retained by the pulmonary tissue and that elimination of bupivacaine by metabolism can be neglegted for lung. The hemodynamic parameters of bronchiolar perfusion in the artificially perfused lung were determined using two fluorochrome-labeled macromolecular proteins, i.e. fluorescein-isothiocyanate (FITC)- and lissamine-rhodamine-B 200 (RB 200)-labeled globulin. After 10 min of perfusion at a flow rate of 12 ml/min in the closed system an area of 10.8% of the peribronchiolar tissue area contained the dye-label FITC. A very similar index (10.1%) of dye-coloured capillaries was obtained when the lungs of anaesthetized rats were examined 10 min after intravenous injection of the fluorochrome into the pulmonary artery in vivo. In isolated perfused rat lungs receiving both FITC and RB 200 59.5% of FITC-labeled capillaries were reached by the second fluorochrome within 2 s. This fraction accounted for 93.3% after 10 s of circulation time. This proves that isolated rat lungs were well perfused in vitro.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169070
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  • 3
    Electronic Resource
    Electronic Resource
    Morphological instabilities in pattern formation by precipitation and crystallization processes (1996)
    Springer
    Geologische Rundschau 85 (1996), S. 19-28 
    Details
    ISSN: 0016-7835
    Keywords: Key words Anastomoses ; Crystal zoning ; Snow bands ; Liesegang rings ; Ostwald ripening ; Self organization ; Siderite ; Supersaturation theory ; Zebra rock
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Morphological instabilities in periodic patterns occurring both in precipitation and crystallization processes (Liesegang rings and crystal zoning) are investigated and compared with similar patterns in geological samples (zebra rocks and mud bands in snow sediments). In classical Liesegang systems, undisturbed parallel or concentric precipitation bands are emanated from even or concentric diffusion sources in homogeneous diffusion matrices of gelatine or other gels. In the case of superposing diffusion sources, sources with undulatory curvatures or local diffusion barriers there may occur several types of instabilities within the sequence of regular patterns: (a) gaps within the bands forming radial alleys free of precipitate, (b) transition from broken bands to speckled patterns and (c) apparent branching of bands linked together by so-called anastomoses. Calculations with a competitive particle growth (CPG) model show that lateral instabilities in Liesegang bands (gaps and radial alleys of gaps) are the result of Ostwald ripening effects taking place after precipitation. Apparent branching of bands or formation of anastomoses can be simulated with a prenucleation model according to Ostwald's supersaturation theory. Similar irregularities can be observed in zebra rocks (e.g. banded siderite) whose bandings are commonly explained by sequential sedimentation processes. A very different mechanism is assumed to be responsible for the origin of mud bands in snow sediments. An initially homogeneous distribution of intrinsic mud in snow sediments can be arranged into parallel bands according to a crystal zoning mechanism which is based on repeated thawing and freezing of the snow sediment due to the daily alternation of sun and darkness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192056
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  • 4
    Electronic Resource
    Electronic Resource
    K-Opioid activity of the four stereoisomers of the peripherally selective κ-agonists, EMD 60 400 and emd 61 753This paper is dedicated to Prof. H.J. Langmann on the occasion of his 70th birthday. (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 6 (1994), S. 685-689 
    Details
    ISSN: 0899-0042
    Keywords: chromatographic resolution of stereoisomers ; molecular modelling ; conformation ; κ-opiate receptor ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The four stereoisomers of the two peripherally selective κ-opioid agonists EMD 60 400 and EMD 61 753 were synthesized, tested for stereoisomeric purity, and examined for affinity to the κ opioid receptor. The relationships between the configuration of these molecules and their biological activity are discussed. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530060814
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  • 5
    Electronic Resource
    Electronic Resource
    Morphological instabilities in pattern formation by precipitation and crystallization processes (1996)
    Springer
    International journal of earth sciences 85 (1996), S. 19-28 
    Details
    ISSN: 1437-3262
    Keywords: Anastomoses ; Crystal zoning ; Snow bands ; Liesegang rings ; Ostwald ripening ; Self organization ; Siderite ; Supersaturation theory ; Zebra rock
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Morphological instabilities in periodic patterns occurring both in precipitation and crystallization processes (Liesegang rings and crystal zoning) are investigated and compared with similar patterns in geological samples (zebra rocks and mud bands in snow sediments). In classical Liesegang systems, undisturbed parallel or concentric precipitation bands are emanated from even or concentric diffusion sources in homogeneous diffusion matrices of gelatine or other gels. In the case of superposing diffusion sources, sources with undulatory curvatures or local diffusion barriers there may occur several types of instabilities within the sequence of regular patterns: (a) gaps within the bands forming radial alleys free of precipitate, (b) transition from broken bands to speckled patterns and (c) apparent branching of bands linked together by so-called anastomoses. Calculations with a competitive particle growth (CPG) model show that lateral instabilities in Liesegang bands (gaps and radial alleys of gaps) are the result of Ostwald ripening effects taking place after precipitation. Apparent branching of bands or formation of anastomoses can be simulated with a prenucleation model according to Ostwald's supersaturation theory. Similar irregularities can be observed in zebra rocks (e.g. banded siderite) whose bandings are commonly explained by sequential sedimentation processes. A very different mechanism is assumed to be responsible for the origin of mud bands in snow sediments. An initially homogeneous distribution of intrinsic mud in snow sediments can be arranged into parallel bands according to a crystal zoning mechanism which is based on repeated thawing and freezing of the snow sediment due to the daily alternation of sun and darkness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192056
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  • 6
    Electronic Resource
    Electronic Resource
    Transformation von Uridin- zu Cytidinderivaten durch selektive Aminierung (1989)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 331 (1989), S. 835-842 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transformation of Uridine Derivatives into Cytidines via Selective AminationThe synthesis of some 5-fluorosubstituted cytidine 2 derivatives via amination of corresponding uridine derivatives 1 is described. 5-Substituted 4-tetrazolo pyrimidinone derivatives 5 are key intermediates in the procedure. The method used is extended to other fluorinated starting materials, e.g. fluorinated uridinedinueleotides 7 or 2′-deoxy-2′-fluorouridine 9. The fluoro containing products are easily available by fluorination with elemental fluorine or hydrogene fluoride.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19893310518
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  • 7
    Electronic Resource
    Electronic Resource
    The toxic effects of organometals on the lands cycle in HL-60 cellsThis paper is the basis of work presented by the author at the International Conference on Environmental and Biological Aspects of Main-Group Organometals, Padua, Italy, 15-19 September 1991 (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 6 (1992), S. 297-303 
    Details
    ISSN: 0268-2605
    Keywords: Organolead ; organomercury ; organotin ; toxicity ; lipid metabolism ; arachidonic acid ; Lands cycle ; cell culture ; HL-60 cells ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The concentration of free fatty acids within cells is mainly dependent upon the following enzyme activities: liberation by phospholipase A2 (PLA2), activation of free acids by acyl-CoA-synthetase and re-esterification by lysophospholipid acyltransferase (LAT). In many cell types, especially those of the haematopeotic system, this deacylation-reacylation cycle (‘Lands cycle’) plays an important role in the regulation of free fatty acid concentration, above all that of arachidonic acid.We have shown here that heavy-metal compounds affect this cycle mainly at two points and thereby lead to an increase of free fatty acids. On the one hand, organometals cause an inhibition of the reacylation of lysophospholipids; and on the other, the induction of PLA2 activity produces the same result. All compounds investigated such as methylmercury chloride (MeHgCl), diethyltriethyl-, and trimethyl-lead chloride (Et2PbCl2, Et3PbCl, Me3PbCl) as well as trimethyltin chloride (Et3SnCl) and di-t-butyltin dichloride (t-Bu2SnCl2) show at least one of these effects. In the case of Et3PbCl, the use of PLA2-inhibitors or pertussis toxin causes a drastic decrease in the amount of arachidonic acid liberated. These experiments demonstrate that the organometallic compounds inhibit the reacylation and/or stimulate the deacylation of fatty acids that are involved in many important biological or pathological mechanisms. The results suggest that in differentiated HL-60 cells the organometal compounds stimulate the Lands cycle by increasing the activity of the PLA2, possibly via a signal-transduction mechanism, and this effect is intensified via an inhibition of reesterification.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590060309
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  • 8
    Electronic Resource
    Electronic Resource
    Borkomplexe von Malonsäureamiden und Malonsäureamidinen (1984)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 370-380 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Boron Complexes of Malonamides and MalonamidinesN,N,N′,N′-Tetramethylmalonamide (4) reacts with triethyloxonium tetrafluoroborate in boiling tetrachloroethane or with diethyl ether  -  boron trifluoride at room temperature to form the tetrafluoroborate 6a which was deprotonated with triethylamine to give 4,6-bis(dimethylamino)-2,2-difluoro-3-oxa-1-oxonia-2-borata-4,6-cyclohexadiene (7). With 4 and boron trichloride in CCl4 the neutral complex 9 is obtained, in CH2Cl2 the chelate complex 10. Similar to diethyl ether  -  boron trifluoride (2-aminoethoxy)diphenylborane (12) and triethylborane (15) condense with 4 to yield the salts 13 and 17, respectively, and the neutral complexes 14 and 16, respectively. N,N,N″,N″- Tetramethylmalonamidine (20) reacts with triethylborane (21a), ethoxydiphenylborane (21b) and trimethoxyborane (21c) to give the neutral complexes 22a-c which partly can be protonated with HBF4 to form the salts 23a, b.
    Notes: N,N,N′,N′-Tetramethylmalonsäurediamid (4) bildet mit Triethyloxonium-tetrafluoroborat in siedendem Tetrachlorethan oder mit Diethylether  -  Bortrifluorid bei Raumtemperatur das Tetrafluoroborat 6a, das sich mit Triethylamin zum 4,6-Bis(dimethylamino)-2,2-difluor-3-oxa-1-oxonia-2-borata-4,6-cyclohexadien (7) deprotonieren läßt. Bortrichlorid liefert mit 4 in CCl4 den Neutralkomplex 9, in CH2Cl2 den Chelatkomplex 10. Ähnlich wie Diethylether  -  Bortrifluorid kondensieren auch (2-Aminoethoxy)diphenylboran (12) und Triethylboran (15) mit 4 zu den Salzen 13 bzw. 17 und zu den Neutralkomplexen 14 bzw. 16. N,N,N″N″-Tetramethylmalonamidin (20) bildet mit Triethylboran (21a), Ethoxydiphenylboran (21b) und Trimethoxyboran (21c) die Neutralkomplexe 22a-c, die sich mit HBF4 teilweise zu den Salzen 23a,b protonieren lassen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198419840217
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  • 9
    Electronic Resource
    Electronic Resource
    Synthesis and Biological Activity of a Potent Renin Inhibitor of the Azapeptide TypeDedicated to Prof. Dr. Hans Joachim Langmann on the occasion of his 70th birthday. (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 1231-1233 
    Details
    ISSN: 0170-2041
    Keywords: Azapeptides ; Renin inhibitor ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A highly potent renin inhibitor of the azapeptide type (2) is synthesized by starting from the hydrazine derivative 3. This peptide analogue inhibits renin in the same range (nanomolar) as its purely peptidic original 2a, but reveals much higher specificity for renin than 2a does.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419941214
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